Oracle: select values only from row with min(id)

SELECT
   ass.assessmentAmount -- want to fetch assessmentAmount of min(ass.assessmentId)
   ass.assessmentId
FROM
   --bunch of joins  
WHERE
ass.assessmentId = (SELECT min(ass2.assessmentId) FROM Assessment ass2
   --same bunch of joins 

It looks very confusing because I have 6 joins with conditions and I don't want to repeat it two times. Is there another way of doing this?